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package org.apache.juneau.rest.vars;

import org.apache.juneau.rest.*;
import org.apache.juneau.svl.*;

/**
 * Servlet init parameter variable resolver.
 * 
 * <p>
 * The format for this var is <js>"$I{key[,defaultValue]}"</js>.
 * 
 * <p>
 * This variable resolver requires that a {@link RestRequest} object be set as a context object on the resolver or a
 * session object on the resolver session.
 * 
 * <p>
 * Values are pulled from the {@link RestServlet#getInitParameter(String)} method.
 * 
 * <p>
 * Since this is a {@link SimpleVar}, any variables contained in the result will be recursively resolved.
 * Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
 * 
 * <h5 class='section'>See Also:</h5>
 * <ul>
 * 	<li class='link'><a class="doclink" href="../../../../../overview-summary.html#juneau-rest-server.SvlVariables">Overview &gt; juneau-rest-server &gt; SVL Variables</a>
 * </ul>
 */
public class ServletInitParamVar extends DefaultingVar {

	/** The name of this variable. */
	public static final String NAME = "I";

	/**
	 * Constructor.
	 */
	public ServletInitParamVar() {
		super(NAME);
	}

	@Override /* Parameter */
	public String resolve(VarResolverSession session, String key) {
		return session.getSessionObject(RestRequest.class, RequestVar.SESSION_req).getContext().getServletInitParameter(key);
	}
}
